Surface mounting has become the preferred technique for circuit board assembly such that numerous if not nearly all types of electronic components have been or are being redesigned for surface mount (that is, leadless) applications. The rapid incorporation of surface mount devices (SMD) into all types of electronic circuits has created a demand for high frequency resistors.
Resistors serve an essential function on many circuit boards. There are many different performance characteristics of resistors for which improvement may be sought to facilitate desired operation. A prior example of technology that addresses certain resistor aspects is disclosed in U.S. Pat. No. 7,830,241 to Lai et al. that discloses a film resistor wherein electrodes are embedded within the film resistive material. According to Lai et al., it had been recognized that untrimmed edges of thin film resistive layers had negatively impacted resistor high frequency response. By burying the electrodes in the resistive material, high-frequency response was improved per the Lai et al. disclosure.
U.S. Pat. No. 7,042,232 to Jacob is directed to a cable and substrate compensating custom resistor. The resistor is designed for use in a combination with a test lead having inductive characteristics. The resistor includes a thin film layer on one side of a substrate. On the other side of the substrate, resistive material extends from one termination point toward (but does not reach) a second termination point. Capacitance formed between the resistive layers compensates for high frequency effects on the combined circuit so that with the inductive characteristics of the probe lead, a relatively flat response is indicated as achievable.
U.S. Pat. No. 6,819,569 to Broman et al. is directed to an impedance equalization module. A resistive (NiCr) layer is applied to a dielectric coating that is supported by a copper (Cu) layer, all of which is supported on an aluminum oxide substrate. Compensating Cu electrodes are provided at each end of the resistive layer and function as capacitor electrode layers with the Cu layer.
A publication by TT electronics (entitled “High Frequency Chip Resistor Terminators”) describes a device that provides a tantalum nitride (TaN) film over a substrate and includes end termination at either end thereof. The device provides an alumina substrate and does not disclose any form of frequency compensation.
The complete disclosures of all the foregoing United States patents and publications are hereby fully incorporated for all purposes into this application by reference thereto.